Machine toe adding- numbers



NELSON.

Calculator.

Patented April 24, 1860.

Mmmismy N, PETERS, Phulu-Llthnylphtr. Wnhingwm D.C-

UNITED STATES PATENT OFFICE.

DAVID R. NELSON, OF JACKSON, OHIO.

MACHINE FOR ADDING NUMBERS.

Specification of Letters Patent No. 28,006, dated April 24, 1860.

To all whom it may concern:

Be it known that I, DAVID R. NELSON, of Jackson, Jackson county, Ohio,have invented a certain new and useful Improvement in Addometers orMachines for Adding Numbers; and I hereby declare the following to be afull, clear, and exact description of the same, reference being had tothe accompanying drawings, making part of this specification.

My improvement consists in a provision of finger keys numbered from 1 to9 inclusive, each when depressed being made through a peculiararrangement of mechanism to act upon and move forward the finger of adial the exact number of units carried on the face of the key itself, sothat when a column of figures have been added by depression of keyscorresponding to the figures of the column, the amount may be read onthe face of the dial.

The accompanying drawing represents by perspective view an instrumentembodying my improvement, with the front portions of some of the keysand a portion of the stop board removed to exhibit the interiormechanism.

A is the frame or box in which the machine is arranged and operated.

B are the finger keys hinged at Z; to box A. They are nine in number andmarked in order with figures from 1 to 9 inclusive. Each is providedwith a spring a used to return it against the stop board C afterdepression.

D is a ratchet wheel journaled in the box A and stop board C, andcarrying on the upper end of its spindle an index or pointer 0, adaptedto move over the face of the dial I). The teeth on the periphery of thewheel D are equal in number to the divisions or units on the dial E sothat a rotation of the wheel to the extent of a given number of teethcarries the finger of the dial over the Zanie number of divisions orunits on the F is a lever hinged at f to the box A and provided with apawl G fitted to work in the ratchet wheel D. The free end 7" of lever Fmoves in the slide d between the stops 6 v6. The keys B are providedwith downwardly projecting brackets g made to present by means ofaccompanying plates h, an inclined face for action on the lever F. Thefaces of the plates are made adjustable by means of curved slots inplates l1 said plates being hinged to the brackets 9 By a properadjustment of plates 71, the exact requisite movements of the lever Fmay be obtained. On the depression of each key, its plate It by itsinclined face moves the lever F, and through the pawl G and ratchetwheel D carries the index 0 around in the direction of the arrow over anumber of divisions or units on the dial corresponding to the figure onthe face of the key. H is a spring serving to restore the lever F to itsforward position when the latter is released by the elevation of thekey. I is a check pawl to prevent backward action of the wheel D in thereturn of pawl Gr after depression of a key.

J, J are springs provided with friction pads 2' made to press on theface of the wheel D to prevent its being carried by momentum to afarther extent of rotation than that given it by the lever and pawl F,G. The pressure of the said springs is adjustable by a set screw 7'. Thecheck pawl I may, if preferred be dispensed with, the friction pads 2'serving to prevent the retrograde motion of the wheel D.

The index 0 is constructed with a spring socket so that it may turn withthe spindle of the wheel D, yet be free to be set by hand independentlyof wheel D to any desired position on the dial.

I claim as new and of my invent-ion herein and desire to secure byLetters Patent The combination of the keys B, adjustable brackets g, h,hinged lever F and pawl G operating through the ratchet wheel D on theindex 0 substantially in the manner and for the purpose explained.

In testimony of which invention, I hereunto set my hand.

DAVID R. NELSON. l/Vitnesses:

G120. H. KNIGHT, C. STIEMER, J R.

